#!/usr/bin/env python3
# coding: utf-8

import numpy as np
import cv2 as cv
img = np.zeros((500,500,3),np.uint8)
pts = np.array([[100,10],[200,200],[70,20],[50,10]],np.int32)
pts = pts.reshape((-1,1,2))
cv.polylines(img,[pts],False,(0,255,255))

cv.imshow('img',img)
cv.waitKey(0)
cv.destroyAllWindows()